The present invention concerns a liquid distribution tray device that improves liquid distribution over the cross sectional area of a vessel following the tray. The device also intimately contacts the liquid and vapor phases to achieve thermal and compositional equilibrium. The device is typically used in a hydroprocessing reactor.
Most of the known designs of liquid distribution devices fall into one of four categories. The first is a series of troughs and overflow weirs to systematically subdivide the liquid into multiple streams before it contacts the bed. This type is often used in liquid contractors or countercurrent absorbers. An example of this type is described in U.S. Pat. No. 5,192,465.
A second type of liquid distribution device is a perforated horizontal tray. This may or may not have notched weirs around the perforations. The tray may also have chimneys for vapor flow. This type of distribution device can be used for rough liquid distribution in conjunction with a more sophisticated final liquid distribution tray. Examples of this type are disclosed in U.S. Pat. No. 4,836,989.
The third common type of liquid distribution device is a chimney tray. This device uses a number of standpipes laid out typically on a regular square or triangular pitch pattern on a horizontal tray. The standpipes typically have holes in the sides for the passage of liquid. The tops of the standpipes are open to allow vapor flow down through the center of the chimneys. Some designs use special vapor downcomer chimneys to handle the bulk of the vapor flow. This type is known from U.S. Pat. No. 4,126,540 and U.S. Pat. No. 3,353,924.
The fourth type of liquid distribution device is a bubble cap tray. This device uses a number of bubble caps laid out on a regular pitched pattern on a horizontal tray.
The bubble cap is a cap centered concentrically on a standpipe. The sides of the cap are slotted for vapor flow. Liquid flows under the cap and, together with the vapor, flows upward in the annular area and then down through the center of the standpipe as described in U.S. Pat. No. 5,158,714.